The invention relates to a method and a base station for functional testing of a transmission and reception path, in particular in a base station of a radio communications system.
In radio communications systems, information such as voice, video information or other data is transmitted through the use of electromagnetic waves through a radio interface between a transmitting and a receiving radio station, such as a base station, or a mobile station in the case of a mobile radio system. The electromagnetic waves in that case are emitted at carrier frequencies which are located in the frequency band provided for the respective system. In the case of the GSM mobile radio system (Global System for Mobile Communication), the carrier frequencies are in the region of 900 MHz, 1800 MHz and 1900 MHz. Carrier frequencies in the region of about 2000 MHz are envisaged for future mobile radio systems using CDMA and TD/CDMA transmission methods through the radio interface, such as the UMTS (Universal Mobile Telecommunication System) or other 3rd generation systems.
According to the prior art, any malfunction or failure of a transmission or reception path of a transceiver in the base station of a mobile radio system can be detected only by testing the respective transmission and reception path when switched off. That is disadvantageous since the radio resources cannot be used during the time period for functional testing. Therefore, the test must be carried out, in particular, at times when the traffic level is low. Furthermore, the test must actually be carried out at the location of the base station, which disadvantageously involves a large amount of technical effort and a long time for the operator of the radio communications system if, for example, the base station is installed at a remote location.
It is accordingly an object of the invention to provide a method and a base station for simple functional testing of a transmission and reception path, which overcome the hereinafore-mentioned disadvantages of the heretofore-known methods and devices of this general type.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for functional testing of transmission and reception paths in a base station of a radio communications system, which comprises providing at least one transmitting/receiving device in the base station for transmitting and receiving signals through a radio interface to and from a radio station; transmitting a first signal at a first transmission power level from the base station to the radio station, determining a first reception strength of the first signal in the radio station, and calculating a first difference value between the first transmission power level and the first reception strength; transmitting a second signal at a second transmission power level from the radio station to the base station, determining a second reception strength of the second signal in the base station, and calculating a second difference value between the second transmission power level and the second reception strength; comparing any difference between the first difference value and the second difference value with at least one threshold value; and deriving a function of the transmission and reception path of the base station from the comparison.
The invention advantageously allows the function of the transmission and reception path to be determined by a simple comparison of determined difference values, which each provide a statement relating to the loss during transmission through the radio interface. This comparison can be carried out in normal operation of the base station, as a result of which there is advantageously no limitation on the radio resources for the functional testing. In this case, signaling information or wanted information can be transmitted, for example, as the signals. Furthermore, the invention advantageously allows the function of the transmission and reception paths to be determined continuously, so that it is possible to react quickly to any faults which occur.
In accordance with another mode of the invention, an alarm signal is generated when a malfunction of the transmission and reception path is determined. This allows, for example, advantageous central detection of the function of the respective transmitting/receiving devices of the base station in a central device of the radio communications system.
In accordance with a further mode of the invention, the difference between the determined difference values is compared with an upper and with a lower threshold value, and the respective function of the transmission or reception path is derived from the comparison. This advantageously makes it possible to determine whether the transmission path or the reception path has a malfunction or is defective.
In accordance with an added mode of the invention, an alarm signal, which indicates a malfunction of the transmission path or of the reception path, is generated in each case if the upper threshold value is overshot or the lower threshold value is undershot.
In accordance with an additional mode of the invention, the difference between the average values of the difference values is determined, in which case the average values are determined over a predetermined time interval. A determination of average values advantageously allows fluctuations in the difference values (caused, for example, by shadowing or other physical interference in the transmission through the radio interface) to be normalized and averaged. Therefore, it is advantageously possible to make a more accurate statement regarding the function of the transmission and reception path.
In accordance with yet another mode of the invention, the method is used in a radio communications system which uses a TDMA subscriber separation method or a combination of a TDMA method with further subscriber separation methods. A joint feature of these methods is parallel use of a frequency band for a plurality of communications links, with the individual links being distinguished by time slots. If combined with a CDMA subscriber separation, subscribers are additionally separated by a respective assignment to spread codes. In this case, the difference can advantageously be respectively determined on a frequency basis or a transmission/reception device basis.
With the objects of the invention in view there is also provided a base station of a radio communications system, comprising a transmitting/receiving device for transmitting a first signal at a first transmission power level to a radio station through a radio interface, and for receiving a second signal transmitted by the radio station at a specific second transmission power level; and a control device for determining a second reception strength of the received second signal, for calculating a first difference value between the first transmission power level and a first reception strength determined in the radio station, and for calculating a second difference value between the second transmission power level and the second reception strength, for comparing a difference between the first difference value and the second difference value with at least one threshold value, and for deriving a function of a transmission and reception path from the comparison.
In accordance with another feature of the invention, there is provided a timer for periodically stimulating the determination of the difference values at a predetermined time interval.
In accordance with a concomitant feature of the invention, the base station is a base station of a mobile radio system or of a wire-free subscriber access system.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and a base station for functional testing of a transmission and reception path, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.